Fuel meter for outboard engines

ABSTRACT

An apparatus and method for determining a parameter related to fuel consumption in an engine are disclosed. An electrical sensor senses an electrical control signal used to control fuel introduced into the engine, such as by controlling a valve or fuel injector of the engine. The electrical sensor generates a measurement signal that is indicative of an electrical parameter such as frequency or voltage of the electrical control signal. A processor receives the measurement signal and uses the measurement signal to determine the parameter related to fuel consumption. The parameter can be volume of fuel consumed, fuel consumption rate, fuel efficiency or other related parameter.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.10/289,631, filed on Nov. 7, 2002, which is based on U.S. ProvisionalPatent Application No. 60/345,155, filed on Nov. 7, 2001, the contentsof which are incorporated herein in their entirety by reference.

BACKGROUND OF THE INVENTION

The outboard engine has undergone substantial changes in recent years.The outboard has for decades functioned as a two-cycle motor. Today,while the two cycle motors remain the standard, the use of fuelinjection and computer control has become commonplace. Additionally,four-stroke outboard motors have been introduced in recent years, whichalso incorporate fuel injection.

The outboard engine has utilized carburetors of various forms for themixture of fuel and air for introduction to a combustion chamber. Withthis method of presenting fuel for combustion, traditional technologyemerged for measuring the amount of fuel consumed by the outboardengine. The technology incorporates measurement by means of a fuelmeter. The device is located along a fuel line that connects the fuelsupply tank and the outboard motor. This meter is used to determine thevolume and rate of fuel consumed by the outboard engine.

The fuel meter commonly incorporates a mechanism such as an impeller.The fuel's motion, mass and volume move the impeller. Measurement of theimpeller movement is correlated to an amount and rate of fuel consumed.Fuel meters have also incorporated an optical metering device to providethe fuel measurement. With such a device, fuel flows from the fuelsupply tank to the outboard engine across an optical sensor, whichobtains an optical measurement of the flow of fuel. This measurement iscorrelated to a fuel amount and rate of consumption.

Such fuel measurement devices are considered invasive because themeasuring device being used is installed within the flow of fuel betweenthe fuel supply tank and the engine. Such a device is disclosed in U.S.Pat. No. 4,590,796. As a result, the flow of fuel can be adverselyaffected by the measuring device. That is, with the introduction of oneof these conventional fuel flow measuring devices, an uninterrupted flowof fuel from the supply tank to the engine cannot be obtained. This canhave a negative impact on such characteristics as precision fuelmeasurement and fuel flow deprivation.

Other fuel measuring means, such as those of the type disclosed in U.S.Pat. No. 5,895,844, utilize multiple sensors that are modified to fitdirectly to and become part of the fuel injector. This means uses twophysical sensors to invasively measure the physical position of theinjectors' mechanical components.

Other fuel meters, such as those of the type disclosed in U.S. Pat. No.4,596,216, measure fuel by measuring engine rotations per minute (RPM).In such systems, measurements of fuel rate and other fuel consumptionparameters are dependent upon engine RPM.

SUMMARY OF THE INVENTION

The invention is directed to a fuel meter and measuring method whichovercome these drawbacks of the prior art. That is, the invention isdirected to a non-invasive technique for measuring fuel consumption andother parameters without having a negative impact on performance of theengine.

The invention is directed to a fuel meter and a method for determining aparameter related to fuel consumption in an engine, such as an outboardengine in a boat. An electrical control signal used to control fuelintroduced into the engine is sensed. A measurement signal indicative ofan electrical parameter of the electrical control signal is generated. Aprocessor receives the measurement signal and uses the measurementsignal to determine the parameter related to fuel consumption in theengine.

In one embodiment, the electrical control signal is sensed by anelectrical sensor. The electrical sensor can be inductively coupled to aline carrying the electrical control signal. Alternatively, theelectrical sensor can be conductively coupled to the line carrying theelectrical signal. In one embodiment, the electrical parameter of theelectrical control signal indicated by the measurement signal is voltageof the control signal. In one embodiment, the parameter is frequency ofthe control signal.

In one embodiment, the control signal controls a valve of the engine. Inone embodiment, the control signal controls a fuel injector of theengine. The volume of the fuel injector can also be used in determiningthe parameter related to fuel consumption in the engine.

The meter and method of the invention can be used to determine one ormore parameters related to fuel consumption in the engine. For example,the parameter can be the volume of fuel consumed, the rate of fuelconsumption and/or the fuel efficiency.

In accordance with the invention, the fuel flow measurement is madeindependent of any measurement of engine RPM.

The engine can be an outboard engine such as an engine on a water craftsuch as a boat. The boat can include a velocity meter for determiningvelocity of the boat. A global positioning satellite system (GPS) canalso be used to determine velocity of the boat. The velocity of the boatcan also be used in determining the parameter related to fuelconsumption in the engine.

In the present invention, because an electrical control signal in theengine is sensed, the fuel flow measurement is non-invasive, that is,there is no equipment introduced into the fuel flow path to effect themeasurement. As a result, the measurement does not interfere with ornegatively affect the operation of the engine. A highly accurate fuelflow measurement can therefore be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features, and advantages of theinvention will be apparent from the following more particulardescription of preferred embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention.

FIG. 1 is a functional block diagram illustrating one embodiment of theinvention.

FIG. 2 contains a schematic functional block diagram illustrating thearchitecture and functional processes of one embodiment of a system inaccordance with the invention.

FIG. 3 contains a schematic plan view of one embodiment of a displayused to display to the user the information generated in accordance withthe invention.

FIG. 4 contains a more detailed functional block diagram of the systemof the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

FIG. 1 is a functional block diagram illustrating one embodiment of theinvention. In this embodiment, the engine 10 to which the invention isapplied is used to propel a water craft such as a boat 9. The engine 10receives fuel from a fuel reservoir or tank 18 via a fuel line 20. Theengine 10 includes a fuel injection system 12 for receiving the fuel anddistributing the fuel via one or more fuel injectors 14 to a combustionsystem 22, which includes one or more combustion chambers or cylinders24 in the engine 10. The engine 10 also includes other componentsgenerally referred to by reference numeral 16.

In one embodiment, the engine 10 includes or is interfaced to a enginecontroller 30, which electronically controls the functions of the engine10. One function of the engine controller 30 is to transmit controlsignals to the fuel injection system 12 to control electromechanicalfuel injectors 14. The engine controller 30 generates a pulse signal foreach injector 14 to control the introduction of fuel into the engine.The pulse signal is typically a series of electrical pulsescharacterized by a fixed and/or variable voltage or amplitude, frequencyand pulse duration. The pulses can be of a square, triangular or anyother waveform. When a pulse is in an active state, its correspondinginjector 14 is activated to introduce fuel into its correspondingcylinder. The control signals are carried on one or more electricallines 33 from the engine controller 30 to the fuel injection system 12.

In one embodiment of the invention, the system can include an electricalsensor 32, which can be inductively coupled to the line 33. In anotherembodiment, the sensor 32 can be directly connected to the line, thatis, it can be conductively coupled to the line. The electrical sensor 32senses amplitude or voltage and frequency of the pulse signalstransmitted to the fuel injectors 14 by the engine controller 30 andgenerates a measurement signal indicative of the sensed pulse controlsignals.

A processor 34 determines the parameter related to fuel consumption inaccordance with the invention. In one embodiment, the processor 34receives the measurement signal from the sensor and uses the measurementsignal in determining the parameter. In another embodiment, theprocessor 34 is directly coupled to the engine controller 30 and isaware of the issuance of the pulse control signals by the controller 30.In either case, the processor 34 in accordance with the inventionreceives information with regard to the amplitude or voltage and/or thefrequency of the pulse control signals. It should be noted that theprocessor 34 can be a separate processor or can be an integral part ofthe engine controller 30.

The processor 34 interfaces to a display and user interface 36. Thedisplay provides the user or boat operator with the fuel consumptioninformation determined by the invention. The user interface allows theuser to alter the configuration of the system, provide input parametersused by the processor to determine the fuel consumption information,select information to be presented on the display and the format of thedisplay, and provide other user-determined information and commands.

The processor 34 also optionally receives inputs related to speed of theboat 9. In one embodiment, a velocity sensor 40 provides the speedinformation. In another embodiment, a global position satellite (GPS)receiver 38 is used in known fashion to provide the speed of the boat 9.The speed of the boat can then be used by the processor 34 to computethe parameter related to fuel consumption.

The following describes the detailed computations performed by theinvention to compute the fuel consumption parameters determined inaccordance with the invention.

In one embodiment, the invention uses a capture sensor to measure thevoltage amplitude, and frequency applied to a fuel injector orinjectors. This capture sensor is attached in proximity to the fuelinjector, or injectors, providing fuel to the combustion chamber. Anelectronic, electromechanical or mechanical device manipulates the fuelinjector, or injectors. This device is integral to the outboard engineitself. The fuel injector supplies an amount of fuel to the combustionchamber. This amount is proportional to the amplitude and frequency ofvoltage applied to the fuel injector.

The fuel injector has a maximum volume of fuel it can contain. A controldevice, integral to the outboard motor, determines the amount of fuelthe injector introduces to the combustion chamber.

The invention determines the volume of fuel the outboard engineconsumes. This is defined as Fuel Consumption (FC). This is determinedby first measuring amplitude and frequency of voltage applied to thefuel injector or injectors. These measurements are then scaled withvalues specific to each type of outboard engine. The result ismanipulated by a value related to the number of cylinders in theoutboard motor as well as a value related to the control configurationof the outboard motor. This is defined as Total Fuel Consumption (TFC).This result is then related to a time interval to determine the rate atwhich fuel is consumed. This is defined as Total Fuel Rate (TFR)

Additionally, in one embodiment, the invention utilizes the speed of theboat as it moves to determine Fuel Efficiency (FE). Speed information iscollected from a device that can determine the speed of the outboardmotor with relation to the fixed earth. As describe above, the devicecan be a speed sensor and/or a GPS receiving system. This value iscommonly known as Speed Over Ground (SOG). The SOG is factored with theTotal Fuel Rate (TFR) to determine the volume of fuel consumed withrespect to the distance the outboard moves, thus defining FuelEfficiency (FE).

With the presentation of Fuel Consumption, Fuel Rate and FuelEfficiency, the operator whose vessel incorporates the outboard engineor engines can determine the effects of their selected throttleposition, motor trim position, trim tabs position, vessel load weightand load location have on fuel usage.

The following parameters related to fuel consumption are computed by theinvention in accordance with the following equations. $\begin{matrix}{{\text{Fuel~~Consumption~~}({FC})} = {\left( {{cylinder}\quad{to}\quad{injector}\quad{parameter} \times \quad{constant}\quad A} \right) \times \quad\left( {{fuel}\quad{injector}\quad{volume}} \right) \times \quad\left( {{constant}\quad I} \right) \times \quad\left( {{voltage}\quad{frequency} \times \quad{constant}\quad B} \right) \times \quad\left( {{voltage}\quad{amplitude} \times \quad{constant}\quad C} \right)}} & (1)\end{matrix}$Total Fuel Consumption (TFC)=FC×number of cylinders   (2)Or:Total Fuel Consumption (TFC)=sum of FC for all cylinders   (3)Total Fuel Rate (TFR)=TFC/((Time differential)×Constant D)   (4)$\begin{matrix}{{{\text{Fuel~~Efficiency~~}({FE})} = {{\text{Total~~Fuel~~Rate}/{distance}}\quad{moved}}}\quad{{{with}\quad{respect}\quad{to}\quad{time}}\quad = {{{TFR}/{SOG}} \times \left( {{Constant}\quad E} \right)}}} & (5)\end{matrix}$

In the above equations the computation of Fuel Consumption is declared.In equation (1) the first product of values, Cylinder to InjectorParameter and Constant A are declared. The Cylinder to InjectorParameter represents a value dependent on the outboard engine's fuelinjection configuration. The first configuration employs a single fuelinjector pump. This single pump supports each fuel injector. Each fuelinjector supports its own individual engine cylinder. The secondconfiguration is one of multiple fuel injector pumps. Each pump supportsits own unique fuel injector. In this configuration, each fuel injectorand pump combination supports an individual cylinder. The value ofConstant A is dependent on the number of cylinders in the engine, andthe fuel pump-injector configuration of the engine.

In equation (1) the second product of values, Fuel Injector Volume andConstant I are declared. Fuel Injector Volume is a volumetric valuedependent upon the maximum volume of fluid that can be supported by anindividual fuel injector. Constant I is a non-dimensional valuedependent on the fuel injectors, incorporated by the outboard engine,being of equal volumetric number.

In equation (1) the third product of values, Voltage Frequency andConstant B are declared. Voltage Frequency is a measured value. Thisvalue is a representation of the frequency of voltage applied to thefuel injector or injectors by the outboard engine control system. Thefrequency represents the number and duration of “pulses” per unit oftime during which the fuel injector or injectors introduce a volume offuel into the associated combustion chamber. Constant B represents avalue defined by the configuration of the fuel injector and outboardengine control system.

In equation (1) the fourth product of values, Voltage Amplitude andConstant C are declared. Voltage Amplitude is a measured value. Thisvalue is a representation of the amount of voltage applied to the fuelinjector or injectors. The amplitude characteristics relate to aspecific volume of fuel which the fuel injector or injectors introduceto the associated combustion chamber. Constant C represents a valuedefined by the voltage amplitude characteristics applied to the fuelinjector by the outboard engine control system. This value is such thatwhen the voltage amplitude characteristics applied to the fuel injectorby the outboard engine control system is such as to introduce to thecombustion chamber a maximum amount of fuel volume, the product ofVoltage Amplitude and Constant C is equal to unity.

In equation (1) Fuel Consumption (FC) is defined as the product of thefirst, second, third and fourth products of values.

In equation (2), Total Fuel Consumption (TFC) is declared. Where theconfiguration of the outboard engine control system is such as to applya consistent volume of fuel to each cylinder over a discrete operatingrange of the engine, the Total Fuel Consumption (TFC) is the product ofthe number of cylinders in the engine and the Fuel Consumption (FC) asdefined in equation (1).

In equation (3), where the configuration of the outboard engine controlsystem is such as to apply a variable volume of fuel to each cylinder,the Total Fuel Consumption is the sum of Fuel Consumptions (FC) asdefined in equation (1), for each cylinder in the engine.

Equation (4) defines Total Fuel Rate (TFR) as the Total Fuel Consumption(TFC), as defined in equations (2) or (3), divided by the product ofTime differential with Constant D. Time differential is defined as thedifference between the end and start of a time interval. The value ofconstant D is such as to provide the appropriate system units to thecomputation.

Equation (5) defines the Value of Fuel Efficiency as the quotient ofTotal Fuel Rate (TFR) and the measured value Speed Over Ground (SOG),then multiplied by a Constant E. The value SOG is measured by a means,such as a velocity meter or GPS receiver system, capable of determiningthe movement of the motor with reference to the fixed earth. The valueof constant E is such as to provide the appropriate system units to thecomputation.

In one embodiment, the volume of an injector is known. A full-lengthpulse of the control signal would introduce the maximum amount of fuelfor that cycle. A measurement of pulse duration therefore indicates theamount of fuel introduced during a cycle. A measurement of a percentageof a full pulse width indicates introduction of fuel during the cycle inan amount proportional to the maximum amount of fuel for a cycle relatedto the percentage of a full pulse width. Referring to equation (1), themeasurement of voltage frequency indicates duration or width of a pulse.

FIG. 2 contains a schematic functional block diagram illustrating thearchitecture and functional processes of one embodiment of a system inaccordance with the invention for computing parameters related to fuelconsumption in an engine, such as an outboard engine on a boat. Thesystem includes an outboard engine or motor 110, which includes anelectronic engine module (EEM) or controller. The EEM includes a datainterface for receiving information related to the control signal usedto control the fuel injectors. Alternatively, or in addition to the datainterface, the EEM can interface to a sensor which detects the controlsignal as it is forwarded from the controller to the fuel injectionsystem. The capture sensor detects, for example, voltage and/or pulserate of the control signal.

A GPS receiving system 138 uses a data interface to provide data relatedto the speed of the boat over the ground (SOG). The EEM and GPS 138interface with a data acquisition module 112, which receives andprocesses the EEM data or capture sensor data. It also collects andprocesses GPS data and applies time tags to the data. The acquired datais then forwarded to a processed data module 114. The data received bythe module 114 can include speed of boat (SOG), control pulse frequencyand control pulse voltage and/or amplitude. The processed data is thenforwarded to a computation module 116 which performs the computationsdescribed above in accordance with the invention.

FIG. 3 contains a schematic plan view of one embodiment of a display 236used to display to the user the information generated in accordance withthe invention. The display can be flush mounted to the boat dashboard orbracket mounted in the boat. In one embodiment, the display contains adigital readout 202 for presenting numerical information to the user.The display 236 also includes LEDs 204, 206 and 208 used to indicate themeaning of the displayed information. For example, when LED 204 isactivated, the displayed information is rate of fuel consumption ingallons per hour (GPH). When LED 206 is active, the displayedinformation is fuel rate in miles per gallon (MPG). When LED 208 isactive, the displayed information is GPH and speed over ground (SOG).The display 236 also provides a user interface in the form of pushbuttons 210 and 212. The user can change the information on the displayby depressing the buttons 210 and 212 in various predeterminedsequences, each of which is associated with a particular item ofinformation presentable on the display.

The various operating modes and display information can be selected bythe user manipulating the buttons 210 and 212. The two buttons 210 and212 are configured as a select button and a change button. The buttonsallow the user to scroll through display modes using the change buttonand, in combination with the select button, allow the user to selectmodes of operation and information to be displayed. For example, some ofthe information that can be displayed and/or modes that can be selectedvia the buttons are:

-   -   Gallons per Hour (GPH), Miles per Gallon (MPG)    -   Gallons per Mile (GPM)    -   GPH and Speed over Ground (SOG)    -   Total Distance Traveled (miles)    -   Present Speed    -   Average Speed (MPH), Average Miles per Gallon    -   Trip Fuel Consumed, Total Fuel Consumed    -   Trip Distance    -   Trip Average Speed, Total Average Speed    -   Standard Engine Selection    -   Custom Engine Selection    -   Fuel Injector ID (1 . . . N Injectors)    -   Fuel Injector Volume (1 . . . N Injectors)    -   Available Running Time at Present Speed (Hours)    -   Fuel Available (Gallons)    -   Fuel Tank Capacity (Gallons)    -   Present Fuel in Tank (Gallons)    -   Fuel Added to Tank (Gallons)    -   Fuel Removed from Tank (Gallons)    -   Select Units (Metric, English)        Each of these modes or items of display information can be        selected using the buttons on the display.

FIG. 4 contains a more detailed functional block diagram of the systemof the invention. The processor 34 can be, for example, an 8052-typemicrocontroller 334. It will be understood that various microprocessorsand microcontrollers may be used. The display 236 can include a backlitLCD for night visibility. The processor interfaces with a flash EEPROM336 for program and configuration storage. The GPS receiver interfacesthrough a 9-pin connector 340 to a RS232 level shifter 338. The sensorinterfaces through a sensor connector 342 and sensor conditioningcircuitry 344. The system can operate from standard 12 VDC boat batterypower via battery conditioning circuitry 346.

The fuel consumption computation system of the invention is anon-invasive technology. The volume and rate of fuel consumed by theoutboard engine is measured indirectly. The technology does not usedirect contact of, or invade the flow of fuel from the fuel supply tank,through the fuel line connecting to the outboard engine. As a result,the system has no impact on engine performance and provides an extremelyaccurate determination with regard to fuel consumption.

While this invention has been particularly shown and described withreferences to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the spirit and scope of theinvention as defined by the following claims.

1. A fuel meter for determining a parameter related to fuel consumptionin an engine, comprising: a sensor for sensing an electrical controlsignal used to control fuel introduced into the engine, the sensingmeans generating a measurement signal indicative of an electricalparameter of the electrical control signal; and a processor thatreceives the measurement signal and uses the measurement signal todetermine the parameter related to fuel consumption in the engine. 2.The fuel meter of claim 1, wherein the sensor comprises an electricalsensor.
 3. The fuel meter of claim 2, wherein the sensor is inductivelycoupled to a line carrying the control signal.
 4. The fuel meter ofclaim 2, wherein the sensor is conductively coupled to a line carryingthe control signal.
 5. The fuel meter of claim 1, wherein the engine isan outboard engine.
 6. The fuel meter of claim 1, wherein the electricalparameter is frequency of the electrical control signal used to controlfuel introduced into the engine.
 7. The fuel meter of claim 6, whereinthe processor uses volume of a fuel injector to determine the parameterrelated to fuel consumption in the engine.
 8. The fuel meter of claim 1,wherein the electrical parameter is voltage of the electrical controlsignal used to control fuel introduced into the engine.
 9. The fuelmeter of claim 8, wherein the processor uses volume of a fuel injectorto determine the parameter related to fuel consumption in the engine.10. The fuel meter of claim 1, wherein the electrical control signalcontrols a valve used to introduce fuel into the engine.
 11. The fuelmeter of claim 1, wherein the electrical control signal controls a fuelinjector used to introduce fuel into the engine.
 12. The fuel meter ofclaim 11, wherein the processor uses volume of a fuel injector todetermine the parameter related to fuel consumption in the engine. 13.The fuel meter of claim 1, wherein the parameter related to fuelconsumption in the engine is volume of fuel consumed.
 14. The fuel meterof claim 1, wherein the parameter related to fuel consumption in theengine is rate of fuel consumption.
 15. The fuel meter of claim 1,wherein the parameter related to fuel consumption in the engine is fuelefficiency.
 16. The fuel meter of claim 1, wherein the measurementsignal is generated independent of a measurement of engine rotations perminute (RPM).
 17. The fuel meter of claim 1, further comprising a GPSreceiver used in determining velocity of a boat propelled by the engine.18. The fuel meter of claim 1, further comprising a velocity meter fordetermining velocity of a boat propelled by the engine.
 19. The fuelmeter of claim 1, wherein velocity of a boat propelled by the engine isused in determining the parameter related to fuel consumption in theengine.
 20. The fuel meter of claim 1, wherein the processor is anintegral part of an engine controller used to control the engine. 21.The fuel meter of claim 1, wherein the processor is an integral part ofan engine controller used to generate the electrical control signal.